Fastener driving tool

ABSTRACT

A tool for firing fasteners into a supporting surface, which tool utilizes compacted pellets of ignitable material as a source of power. A compound firing chamber is provided to facilitate loading with a pellet magazine, a pellet feed being positioned in the handle of the tool. The tool is cocked for firing by pushing the barrel against the supporting surface, and cannot be otherwise fired. The tool preferably includes a fastener-driving member in the form of a piston and the piston can be automatically returned to a plurality of driving or firing positions to vary the power of the tool for a given propellant load.

I United States Patent 11 1 3,659,768 Brunelle 1 May 2, 1972 [54] FASTENER DRIVING TOOL 3,565,313 2 1971 Seghezzi ..227 10 [72] Inventor: Lawrence J. Brunelle, East Haven, Conn. Primary Examiner Granvme Y. Custer Jr. [73] Assignee: Olin Corporation Attorney-Donald R. Motsko, H. Samuel Kieser and W. W. 22 Filed: June 12, 1970 [2]] App]. No.: 45,651 [57] ABSTRACT A tool for firing fasteners into a supporting surface, which tool U.S. utilizes compacted pellets of lgnltable material as a ource of power. A compound firing chamber is provided to facilitate [58] Fleld of Search ..227/8, 9, l0, 1 1 loading with a pellet magazine, a pellet feed being positioned in the handle of the tool. The tool is cocked for firing by push- [56] References Cited ing the barrel against the supporting surface, and cannot be UNITED STATES PATENTS otherwise fired. The tool preferably includes a fastener-drivmg member 1n the form ofa p1ston and the plston can be auto- 3,l7l,l31 3/1965 De Caro et a1 ..227/l0 maticany returned to a plurality f d i or fi i positions 3,3 30,108 7/1 7 Kuaule BI X to vary the power of the tool for a given propellant load. 3,540,141 l1/l970 Butler ..227/1O X 3,549,074 12/1970 Brunelle ..227/l0 X 23 Claims, 14 Drawing Figures Patented May 2, 1972 4 Sheets-Sheet l INVENTOR LAWRENCE J BRUNELLE 4 Sheets-Sheet 3 INVENTOR LAWRENCE J. BRUNELLE ATTORNEY Patented May 2, 1972 Patented May 2, 1972 4 Sheets-Sheet 3 INVENTOR I LAWRENCE J BRUNELLE BY M191 MW ATTORNEY Patented May 2, 1972 4 Sheets-Sheet 4 NQ MW INVENTOR I LAWRENCE J BRUNELLE ATTORNEY FASTENER DRIVING TOOL This invention relates generally to improvements in tools for driving fasteners and the like into masonry, concrete, wood, steel, or the like. More particularly, this invention relates to tools utilizing a combustible propellant charge as a source of power to drive such fasteners.

The use of compacted caseless pellets of nitrocellulose or other combustible material as a power source for a fastenerdriving tool has become widespread in the industry as a result of lowered costs as compared to conventional cased propellant charges. While the use of caseless charges has resulted in cost savings, problems relating to scaling the firing chamber, automatic feeding of pellets into the firing chamber, power output, and the like have arisen from the use of this new propellant fonn.

Since the pellets do not include a metallic casing, greater care must be taken to seal the firing chamber against combustion gas leakage, a function which was previously fulfilled by the casing. It has been found that proper burning of the caseless pellet and proper sealing of the firing chamber can best be achieved by providing a firing chamber which substantially completely surrounds the side surfaces as well as the front and rear surfaces of the pellet. This support of the pellet in the firing chamber is necessary to insure that the pellet will not merely disintegrate when struck by a firing pin, and further to provide lateral sealing which is otherwise provided by the casing in a cased charge.

The fact that the pellet must be supported around substantially its entire periphery when chambered causes further problems concerning automatic feeding of pellets from a magazine into the chamber. Caseless pellets are comparatively fragile by nature and thus should preferably be subjected to a minimum of handling during loading. Ifthe pellet chamber includes a sidewall which surrounds the lateral periphery of the pellet, the pellet must either be manually inserted into the chamber, or else must be mechanically moved from a magazine into a position in axial alignment with the chamber, and then mechanically moved axially into the chamber. Such compound mechanical movement is relatively undesirable because of the complexity of the mechanisms needed to achieve this movement and because of the fragileness of the pellets, and manual loading of the pellets is undesirable because of time loss in its performance.

This invention solves the problem of chambering a pellet by providing a compound or split chamber, a portion of which is formed on the forward face of the bolt, and a portion of which is formed on the barrel recess which receives the nose of the bolt. The portion of the chamber formed on the bolt nose includes an opening which extends laterally with respect to the axis of the bolt. Thus a pellet can be moved laterally through the opening into frictional engagement with the portion of the chamber disposed on the bolt nose. A plunger mechanism is mounted in the tool to pick up pellets from a magazine and transfer them to the bolt nose, with the plunger movement being restricted to a straight linear path. Once the pellet is frictionally engaged by the bolt nose, the plunger is retracted and the bolt nose is telescoped into the barrel recess where the circumference of the chamber is completed.

The invention further includes a biased pellet follower which moves through the pellet magazine and drives pellets out of the magazine, one by one and into engagement with the plunger.

Power-actuated tools of the piston variety, wherein a piston is driven by combustion of a propellant to, in turn, drive a fastener into a supporting surface create problems relating to the return of the piston from its driven position to its driving position. These problems have been solved by providing a barrel which is reciprocally mounted on the receiver portion of the tool, and by mounting a pawl on the receiver, which pawl extends into the barrel to contact the piston. Thus when the barrel is slid forward with respect to the receiver after the piston has been driven, the pawl engages the piston and moves the latter rearward in the barrel to its driving position. It is 'the power output by means of a drum which is rotatably mounted on the receiver for abutting engagement with the barrel when the latter is slid forward with respect to the receiver. The drum is formed with a stepped-end surface providing a variable stop means for contacting the barrel. Thus by rotating the drum, a preselected one of the steps can be brought into position for contacting the barrel to stop the latter after a preselected amount of movement. The drum steps can be accurately calibrated to provide a precisely variable power output for the piston.

In order to insure safe operation of a fastener-driving tool, it is preferable that the tool be incapable of being fired except to drive a fastener into a supporting surface. In order to achieve this object, the tool of this invention is provided with a cocking slide which is movably mounted in the receiver. The cocking slide carries a sear member which engages the firing pin. The cocking slide is ordinarily biased into a position wherein the firing pin is not cocked. The barrel slides rearwardly against the cocking slide to push the latter rearwardly, thus moving the sear rearwardly against the firing pin to cock the latter. When the cocking slide is moved to its rearwardmost position, a lug mounted on the sear is moved into alignment with the trigger so that actuation of the trigger pivots the sear away from the firing pin to release the latter to be driven forward against the propellant charge. Thus the trigger can only contact the sear lug when the firing pin is fully cocked. Therefor the tool cannot be free fired.

It is therefore an object of this invention to provide a tool for driving fasteners, wherein the tool is particularly adapted to accomodate caseless propellant pellets.

It is a further object of this invention to provide a tool of the character described wherein the firing chamber is of compound configuration to permit lateral insertion of a pellet into the chamber.

It is yet another object of this invention to provide a tool of the character described wherein pellets are automatically fed from a magazine into the chamber.

It is still another object of the invention to provide a tool utilizing a piston for driving fasteners wherein the power output of the piston can be varied without varying the size of the propellant charge.

It is another object of this invention to provide a piston-type tool of the character described wherein a drum having a stepped surface is mounted on the tool for contact with a slidable barrel portion thereof, the drum being operable to align various steps thereon with the barrel to vary the extent of forward movement of the barrel utilized to return the piston from a driven position to a driving position.

Yet another object of this invention is to provide a tool of the character described which cannot be free fired, and which can only be fired when pressed against a work piece into which a fastener is to be driven.

These and other objects and advantages of the tool of this invention will become more readily apparent from the following detailed description of a preferred embodiment when read in conjunction with the accompany drawings, in which:

FIG. I is a perspective view of a preferred embodiment of the tool of this invention;

FIG. 2 is a perspective view of a pellet magazine adapted for use with the tool of FIG. 1;

FIG. 3 is an end view of the magazine of FIG. 2;

FIG. 4 is a horizontal sectional view of the handle portion of the tool taken along line 4-4 of FIG. 1;

FIG. 5 is a vertical sectional view of the tool taken generally along line 5-5 of FIG. 4;

FIG. 6 is an exploded perspective view of the cocking slide assembly and sear preferred for use with the tool of this invention;

FIG. 7 is a vertical sectional view of the firing chamber area of the tool taken along line 77 of FIG.

FIG. 8 is a horizontal sectional view of the firing chamber area of the tool taken along line 8-8 of FIG. 7;

FIG. 9 is a partial vertical sectional view of the receiver area of the tool showing the operation of the trigger and sear when the tool is fired;

FIG. 10 is a vertical sectional view, withparts removed for clarity, of the tool showing the position of the piston after a fastener has been driven into a supporting surface and pushdown has been released, and showing the action of the pawl used to engage the piston to return the latter to a driving position when the barrel is moved forward;

FIG. 11 is an exploded side view of the plunger portion of the pellet loader which transfers pellets from the magazine area to the firing chamber;

FIG. 12 is a side view of a portion of the plunger assembly showing the manner in which a pellet is held in place on the plunger;

FIG. 13 is a side sectional view of the receiver area of the tool showing operation of the plunger to transfer a pellet into the firing chamber; and

FIG. 14 is a side sectional view of the barrel and related receiver area of the tool showing the operation of the power adjustment in stopping the barrel when the piston is returned to its driving position.

Referring to FIG. 1, a preferred embodiment of the tool is shown. The tool includes a housing or receiver 2 in which is slidably mounted a barrel member 4. An interchangeable muzzle bushing 6 is screwed into the muzzle end of the barrel 4 to hold a fastener to be driven, the bushing 6 being interchangeable with other bushings adapted for particular sizes of fasteners. A handle portion 8 is secured to the receiver housing 2 so that the tool can be easily gripped by the operator. A resilient recoil pad 10 is mounted on the rear of the handle 8 to absorb recoil shock imparted to the hand of the operator when the tool is fired. A trigger 12 is pivotally mounted on the receiver housing 2. A power adjustment drum 14 is rotatably mounted on the receiver housing 2 adjacent to the barrel 4 and a piston return pawl 16 is mounted at the forward end of the receiver housing 2. The operation of the drum l4 and pawl 16 will be more fully set forth hereinafter.

A magazine slot 18 is disposed in the handle 8 and is preferably open to the atmosphere. A pellet follower, indicated generally by the numeral 20, is slidably mounted in the magazine slot 18, and a magazine 22 containing a plurality of caseless compacted propellant pellets 24 is shown mounted in the magazine slot 18. The pellets 24 are preferably formed from compacted fibrous virgin nitrocellulose, and can be formed with or without a primer; however, it is noted that any caseless pellet which can be ignited to produce pressurized ignition gases can be used with the tool of this invention.

As shown in FIGS. 2 and 3, the magazine 22 is preferably in the form of an open ended elongated tubular member having a gap 26 which extends for the full longitudinal length of the magazine. The member forms an internal cavity 28 which has a cross-sectional configuration which conforms to the shape of the pellets 24, so that the pellets are frictionally retained in the magazine 22 but can be slid outwardly therefrom when acted upon by the pellet follower 20.

Referring to FIG. 4, the pellet follower includes a main body portion 30 having a raised hump 32 which projects outwardly through the magazine slot 18 so that the operator can grasp the hump 32 and manually move the follower 20 through the magazine slot 18. The body 30 also includes a pair of legs 34 which extend laterally and are slidably disposed in a track 36 in the handle 8. A pin 38 is connected to the follower body 30 to extend downwardly therefrom through the magazine gap 26 and a pellet pusher 40 is pivotally mounted on the pin 38. Thus the pusher 40 is able to pass through the interior of the magazine 22. A negator spring 42 is secured to the body member 30 and is operative to pull the entire follower assembly upwardly through the handle so that the follower 20 is operative to push pellets upwardly out of the magazine.

Referring now to FIG. 5, it is noted that a pellet passage 44 extends upwardly from the magazine slot 18 and curves over at 45 to a location above a plunger assembly indicated generally by the numeral 46. The way in which the pusher 40 is able to move the last pellet in the pellet passage 44 onto the plunger assembly 46 is best shown in FIG. 9. The pusher 40 has a laterally protuberant nose portion 41 which is curved like a pellet, and also has a rearward projection 43 which engages the curved part 45 of the pellet passage 44. Thus the curve 45 causes the pusher 40 to pivot about its mounting pin to move the nose 41 toward the plunger assembly 46 to force the last pellet to engage the plunger assembly 46 in a manner more clearly set forth hereinafter. ,The exact operation of the plunger assembly 46 will be described in greater detail hereinafter. It is noted that a shoulder 48 is formed at the lower end of the track 36 so that the follower 20 can be moved downwardly and hooked onto the shoulder 48 to temporarily restrain the follower in the position 20' (shown in phantom) to clear the magazine slot 18 for the removal of an empty magazine and insertion of a fresh one.

The receiver housing 2 contains a bolt assembly 50 which has an axial, stepped passage 52in which is slidably mounted a firing pin 54. A spring member 56 engages the firing pin 54 to bias the latter forwardly when the pin 54 is in its cocked position, as shown in FIG. 5. The forward end portion or nose 50 of the bolt 50 is reduced in size and includes a pair of forwardly extending prongs 58 formed on the lateral sides thereof. The prongs 58 form the lateral sides of the compound firing chamber in which a pellet 24' to be fired is positioned. A plurality of gas-sealing grooves 60 are cut into the bolt 50 to obturate rearward flow of combustion gases. A slot 51 is cut through the receiver housing 2 to permit manual unloading of the tool when the barrel 4 is slid forward should the operator desire not to fire a loaded charge.

The rearward end of the barrel 4 is countersunk as at 62 to telescope over the bolt nose 50' and completely surround the latter to form a gas-sealing shroud around the pellet 24 when the tool is cocked. A pair of shoulders 64 are formed inside of the countersink 62 with the radially inner faces of the shoulders 64 being formed to support the upper and lower side wall portions of the chambered pellet 24'. Thus the compound firing chamber is fomied by the bolt prongs 58 and the barrel shoulders 64 which combine to provide four side lateral support which provides less than complete peripheral confinement for a chambered pellet 24, as is most clearly shown in FIG. 7. This four sided support will aid the chambered pellet 24 in properly breaking up when struck by the firing pin 54, and will promote proper combustion of the pellet. Since the pellet is not completely peripherally supported, it can break up when struck by the fin'ng pin and thus can be more completely burned. The inner walls of the prongs 58 are provided with notches 59 which deform and grip the sides of the pellet 24' due to an inherent small degree of resiliency in the material from which the pellet is formed (See FIG. 8). Forward of the shoulders 64, the interior of the barrel 4 is enlarged to form the main barrel bore 66. An anvil member 68 is rigidly secured in the barrel bore 66 to provide a surface against which the chambered pellet 24 is crushed by the firing pin 54. A plurality of passages 70 extend through the anvil 68 to permit passage of combustion gases from the chamber area into the barrel bore. A piston 72 having an enlarged head portion 74 and a reduced stem portion 76 is slidably mounted in the barrel bore 66, and is shown in FIG. 5 in its firing position. A resilient friction ring 78 is preferably mounted in a groove 80 in the piston head 74 to aid in providing seal between the piston 72 and the barrel bore 66. The forward end of the piston stem 76 provides the means for driving a fastener 82 into a supporting surface 84. An annular buffer pad 86 of plastic or the like is mounted in the barrel bore 66 adjacent to the muzzle bushing 5 to absorb the energy of any over shooting of the piston which might occur.

The piston-retum pawl 16 is mounted on the receiver housing 2 and extends laterally therefrom, a spring 88 being operative to bias the pawl 16 into the barrel bore 66. When the device is pushed down against a work surface as shown in FIG. 5, the barrel 4 is pushed into the receiver housing 2 so that an angled surface 90 formed on the barrel 4 moves against a complementary surface 92 on the pawl 16 to force the latter to move out of the barrel bore 66 against the bias of the spring 88. Thus the nose of the pawl 16 will not be damaged by any over shooting of the piston which might occur.

The power adjustment drum 14 is rotatably mounted on the receiver housing 2 by means of a shaft 94. A portion 96 of the drum 14 is radially enlarged with respect to the remainder 98 of the drum so as to form a rearwardly facing annular shoulder which is stepped as at 100, 102, 104, 106 and 108. The enlarged portion 96 is sized so as to project into a slot 110 which extends longitudinally along the barrel. Thus by rotating the drum 14, any one of the steps 100, 102, 104, 106 and 108 can be moved into the barrel slot 110. The purpose of the steps is to provide a stop which will contact the end wall 112 of the slot 1 and limit the extent of forward movement of the barre] 4 utilized to return the piston 72 from its fired position to its firing position. A ball detent 114 is mounted on the drum 14 to hold the latter against accidental rotational movement away from the desired setting. The detent 114 is, of course, not strong enough to hinder intentional rotation of the drum 14 to effect a new power output. By way of explanation of the operation of the power output adjustment, the distance 116 between the rear face of the piston head 74 and the forward face of the anvil 58 defines a chamber into which combustion gases expand through the anvil passages 70. The larger the volume of this chamber, the lower the power output of the piston since energy will be lost by the gases expanding to fill the chamber before acting on the piston 72. It will be readily appreciated that if the step 100 is disposed in the barrel slot 1 10, the forward movement of the barrel 4 will be stopped sooner than if the stop 108 is in the slot 110. Thus the distance 116 will be greater, resulting in a lower power output. On the other hand, if the step 108 is in the slot 110, the distance 116 will be smaller resulting in a higher power output. The distance 116 can be very accurately correlated to a predetermined power output for any given pellet size, thus the steps 100, 102, 104, 106, 108, etc. can be precisely calibrated to give a wide range of power outputs to greatly increase the versatility of the too]. Of course, indicia can be placed on the drum 14, or a manual can be used with the tool to inform the operator of the power output for any particular drum setting in conjunction with any particular pellet charge.

Referring now to FIGS. 5 and 6, the cocking slide assembly is shown in particular detail. This assembly includes a slide member 118 which is reciprocally mounted on the receiver housing 2. The slide 118 includes a web portion 120 which is aligned with the rear face 22 of the barrel 4 for contact therewith. A spring 124 contacts the slide 118 to bias the latter toward the muzzle of the tool. A sear 126 having a central portion 128 substantially aligned with the axis of the firing pin 54, and a lateral portion 130 offset to one side of the central portion 128 is pivotally mounted on a pin 132 secured to the slide 1 18. It is noted that the lateral portion 130 of the sear is disposed below the slide web 120, and the central portion 128 extends to the rear and upwardly of the slide web 120. A spring 134 is mounted on the slide 118 and contacts the sear 126 to bias the latter in a counterclockwise direction about the pin 132. A lug 136 is secured to and extends laterally inwardly from the forward end part of the lateral portion 130 of the sear. A notch 138 is formed on the sear for engagement with the firing pin 54 to hold the latter in a cocked position, as shown in FIG. 5. A trigger 140 is pivotally mounted on a pin 142 secured to the receiver housing 2. A spring 144 contacts the trigger 140 to bias the latter in a clockwise direction about the pin 142. A springy plate 146 is secured to the trigger 140 and projects upwardly from the rear face thereof, the function of the springy plate 146 being to contact the sear lug 136 to pivot the sear notch 138 out of engagement with the firing pin 54 when the trigger 140 is pulled.

The cocking slide assembly operates in the following manner. When the tool is pushed against the support surface 84, the barrel 4 moves rearwardly against the slide web and causes the slide assembly to move rearwardly against the bias of the spring 124. The scar notch 138 thus moves rearwardly pushing the firing pin 54 rearwardly against the bias of the firing pin spring 56 and to the cocked position. When the rear face of the barrel 4 contacts the bolt 50, the tool is in its full push-down position. When this occurs, the sear lug 136 is aligned with the springy trigger plate 146 so that when the trigger is pulled, the sear 126 will pivot in a clockwise direction and disengage the notch 138 from the firing pin 54 thus freeing the latter to be driven forward by the spring 56. Until full push down is reached, the sear lug 136 will be forwardly ofiset from the springy trigger plate 146 so that pulling the trigger 140 will be ineffective to release the sear 126 from the firing pin 54. Thus the tool can only be fired at full pushdown, and further the tool is never cocked unless it is pushed down against a working surface, so that free firing of the tool is impossible. Still further, the tool cannot be fired by first pulling the trigger and subsequently pushing the tool down because the sear lug 136 will then merely move against the springy trigger plate 146 causing the latter to simply deflect rearwardly and thus fail to cause the necessary pivoting of the sear 126 to occur. Thus stab firing is prevented. Finally, the tool cannot be drop fired since the sear and'trigger spring plate are not longitudinally aligned. FIG. 9 shows the position of the various components when the tool is fired. It is noted that the spring 56 drives the firing pin 54 forward so as to momentarily compress a return spring 57 and permit the pellet to be crushed and ignited. The return spring 57 then recovers sufficiently to move the firing pin 54 rearwardly to the position shown in FIG. 10 to clear the chamber for reloading.

Referring now FIGS. DIGS. 10-13, the loading assembly and its mode of operation are shown. The plunger assembly includes a plunger rod 148 which is slidably mounted in a collar member 150, and which includes a flattened and enlarged head 152 on top of which is fed a pellet 24 from the pellet passage 44. A spring clip 154 is mounted in a groove 156 in the collar and includes a spring finger 158 which extends beyond the top edge of the collar 150 to grip the pellet 24 in conjunction with rigid finger 159 intergral with the collar 150 and hold the pellet in place on the rod head 152, as is best shown in FIG. 12. The rod 148 is screwed into a base 160 which in turn is screwed into a cam block 162. A spring 164 is sandwiched between the collar 150 and the base 160 and is operative to bias the collar 150 away from the base 160 to such an extent that the fingers 158 and 159 normally extend upwardly above the rod head 152 to grip a pellet 24. The cam block 162 includes a cam slot 166 extending longitudinally thereon and having an intermediate skew portion 168, the beginning and end of the skew portion 168 being offset from each other at an angle of approximately 90. The plunger assembly is slidably mounted in a bore 170 in the handle 8 and a spring member 184 is mounted in the bore 170 to bias the plunger assembly away from the firing chamber and downwardly with respect to the handle. A stud 174 is threaded into the handle 8 and includes a projection 176 which is disposed in the cam slot 166. An operating block 178 is mounted in the bore 170 below the cam block 162, and a handle 180 is secured to the operating block 178 and projects through a slot 182 in the handle for access to the operator.

The top of the operating block 178 is preferably rounded as at 183 to permit easy rotation of the cam block 162 with respect to the operating block 178.

The plunger assembly is movable between a pellet-receiving position, shown in FIG. 5, and a pellet-feeding position, shown in FIG. 13. When the plunger is in its pellet-receiving position, the planes of the spring finger 158 and rigid finger 159 are generally parallel to the front and rear walls of the pellets so that a pellet 24 can be slid from the pellet passage 44 into the grasp of the fingers 158 and 159 and thus held in position on top of the plunger assembly. After the tool is fired, and push down is released, the spring 124 forces the cocking slide 118 to move forward on the tool and also forces the barrel 4 to move forward a predetermined distance away from the bolt 50 as shown in FIG. 10. This movement of the cocking slide 118 positions an opening 119 therein above the plunger assembly. Thus the cocking slide 118 will not hinder feeding of a pellet 24 provided the tool is not pushed down for firing. When the tool is pushed down for firing, the cocking slide 118 provides additional sealing between the firing chamber and pellet magazine. FIG. 10 also illustrates how the pellet pusher 40 pivots about its pin 38 when the pusher projection 43 touches the curved side wall 45 of the pellet passage 44 to push the last pellet in the passage 44 onto the plunger assembly. It is noted that the nose portion 41 of the pellet pusher 40 is shaped like a pellet so that it acts like a pellet to move the next preceding pellet onto the plunger assembly as previously explained without interfering with the operation of the plunger assembly.

it will be noted that the firing chamber, being compound or split, permits laterally directed feeding of pellets from the magazine. The barrel portion of the chamber combines with the bolt prongs to provide support for the pellet when the latter is fired and yet permit the pellet to properly break to promote complete combustion thereof.

By providing a cocking slide and sear which is not aligned for actuation by the trigger unless the tool is pushed down against a work surface, additional safety is provided in that the tool cannot be free fired, stab fired or drop fired. When the trigger is actuated to pivot the sear, the latter is swung completely free of the firing pin so that the firing pin moves freely toward its fired position, thus the assembly provides for a safe and smooth trigger action with dependable, nonobstructed firing.

The provision of a plunger assembly mounted in the handle of the tool permits the use of a pellet magazine holding a number of pellets and insures that each pellet will be automatically and properly seated in the firing chamber when the plunger is actuated. Thus manual fumbling with pellets during loading is eliminated. In order to maintain a slender and readily graspable handle, the pellets are preferably disposed in the handle with their diametric dimension parallel to the axis of the tool, and the plunger picks up a pellet from the magazine and pivots the pellet through a 90 angle as the pellet is transfercd upwardly to the chamber.

The use of a rotating drum to vary the amount of forward movement of the barrel when the piston is returned to a firing position permits a greater number of power settings to be imparted to the tool for any one size pellet charge. The power settings can be very accurately calculated and indicia setting forth particulars thereof can be readily placed on the drum so that the operator can quickly adapt the tool to a great variety of power outputs which he may desire for a given propellant charge.

In order to open the chamber for loading, the barrel 4 is then grasped and slid forward as shown in FIG. 14 so that the chamber area appears as shown in FIG. 13. The handle 180 is then pushed upward by the operator causing the cam block 162, rod 148 and collar 150 to move upward, and also compressing the spring 184. The stud projection 176 passes through the skew portion 168 of the cam slot 166 causing the cam block 162, rod 148 and collar 150 to rotate through an angle of about 90, thus rotating the pellet 24 into the proper position for insertion between the bolt prongs 58. As upward movement of the plunger assembly is continued, the rigid finger 159 abuts the bolt nose 50' to terminate upward movement of the collar 150 and fingers 158 and 159. Still further upward movement of the cam block 162 causes the rod 148 to move upwardly with respect to the collar 150 thus compressing the spring 164 and pushing the pellet 24 upward out of the grasp of the fingers 158 and 159 and between the bolt prongs 58. As previously noted the bolt prong slots 59 slightly deform the advancing pellet 24 and grip the latter. The handle is then released permitting the springs 164 and 184 to return the components of the plunger assembly to their starting positions shown in FIG. 5 and leaving the pellet 24 wedged between the bolt prongs 58.

Referring to FIG. 14, the barrel 4 is moved forward with respect to the housing 2, thus moving the piston head 74 against the return pawl 16. Since the pawl 16 is secured to the receiver housing 2, forward movement of the barrel 4 causes the piston 72 to slide rearwardly in the barrel toward the anvil 68. Thus the piston is returned to its firing position by the pawl 16. After the piston 72 has reached its firing position, and after the pellet 24 has been placed between the bolt prongs 58 by the plunger assembly, the barrel 4 is moved rearwardly to the position shown in FIG. 10 wherein the tool is ready for push-down after a fastener has been placed in the muzzle bushing.

Although reference has been made to a particular embodiment of this invention, it will be obvious that other modifications and alterations will readily suggest themselves to those skilled in the art. Accordingly, the scope of this invention should be ascertained from the following claims.

I claim:

1. A power-actuated tool comprising:

a. a housing;

b. a barrel mounted in said housing;

c. first opposed wall means in said barrel forming a first portion of a split firing chamber;

second opposed wall means in said housing forming a second portion of said split firing chamber;

e. said first and second wall means being operative to be moved into circumferentially adjacent positions to provide at least four-sided close confinement of a propellant charge positioned for firing in said split firing chamber, and further being operative to be moved into offset positions to permit a propellant charge to be inserted from a lateral direction into frictional engagement with one of said first and second means; and

f. means in said housing operative to ignite a propellant charge positioned in said split firing chamber.

2. A power-actuated tool comprising:

a. a housing;

b. a barrel mounted in said housing for reciprocal movement therein;

c. a pair of opposed shoulders in said barrel providing first opposed wall means forming a first portion of a split firing chamber;

d. a pair of opposed forwardly protruding prongs mounted in said housing to provide second opposed wall means forming a second portion of said split firing chamber, said prongs being telescoped between said opposed shoulders when said barrel is in a rearwardmost position whereby said first and second wall means circumferentially adjacent and operative to provide four-sided confinement of a propellant pellet positioned for firing in said split firing chamber; and

e. means in said housing operative to ignite a propellant pellet positioned in said split firing chamber.

3. A power-actuated tool comprising:

a. a housing;

b. a barrel mounted in said housing, said barrel having a rearward portion including a cavity opening into said housing;

c. first opposed wall means in said barrel cavity forming top and bottom portions of a split firing chamber;

d. bolt means mounted in said housing, said bolt means having a nose portion sized for telescoping containment in said barrel cavity;

e. prong means formed on said bolt nose and extending therefrom to form lateral side portions of said split firing chamber, said prong means being sized for telescoping extension between said first wall means to combine therewith to provide a four-sided split firing chamber;

f. one of said barrel and said bolt means being movable with respect to the other thereof to displace said first wall means from said prong means to open said split firing chamber for insertion of a caseless propellant pellet; and

g. means in said housing operable to ignite a propellant pellet.

4. The tool of claim 3, further including means on said prong means operative to deform a propellant pellet to grip the latter.

5. A power actuated tool comprising:

a. a housing;

b. a barrel slidably connected to said housing and movable between a cocked position and a fired position;

c. a firing pin slidably mounted in said housing and movable between a cocked position and fired position;

d. firing spring means contacting said firing pin to bias the latter toward said fired position;

e. slide means mounted in said housing and movable between a forward position and a rearward cocked position, said slide means including a portion aligned with said barrel to contact the latter when said barrel is moved rearwardly whereby said slide means is driven rearwardly to its cocked position by said barrel;

f. sear means pivotally mounted on said slide means and operable to engage said firing pin to cock the latter when said slide means is cocked;

g. trigger means pivotally mounted on said housing, said trigger means including a plate projecting therefrom toward said slide means; and

h. lug means projecting from said sear means for alignment with said trigger plate only when said slide means is in its cocked position, said trigger plate being operative to engage said sear lug, when said trigger is pulled, to pivot said rear means out of engagement with said firing pin to release the latter for movement toward its fired position.

6. The tool of claim 5, further comprising spring means contacting said slide means to bias the latter toward its forward position.

7. The tool of claim 5, further comprising second spring means contacting said firing pin to bias the latter a short predetermined distance away from its fired position after the tool is fired.

8. A power-actuated tool comprising:

a. housing means;

b. barrel means slidably carried by said housing means, said barrel means including a relatively narrow slot extending longitudinally thereof;

. piston means mounted in said barrel means and movable between a fired position and a firing position; a firing chamber rearward of said piston means;

e. pawl means mounted on said housing means and operative to engage said piston means to move the latter from its fired position to its firing position when said barrel means is moved forwardly with respect to said housing means, said pawl means extending through said barrel slot; and

f. cylindrical means mounted on said housing for rotation about its own axis and operable independently of said pawl for engagement with an end wall of said slot in said barrel means to stop forward movement thereof at a plurality of selectable locations to position said piston means at any one of a number of different distances from said firing chamber to vary the power output of the tool with a given propellant load.

9. The tool of claim 8, wherein said cylindrical means is a drum rotatably mounted on said housing, said drum having an end surface including steps longitudinally offset one from another, each of said steps being positionable in said barrel slot by rotation of said drum to align a step with said end wall of said barrel slot to stop forward movement of said barrel at a different location forward of said housing.

10. The tool of claim 9, further comprising detent means operable to fix said drum against accidental rotational movemerit once a predetermined step is aligned with said barrel slot end wall.

11. A power-actuated tool comprising:

a. a housing;

b. a barrel connected to said housing, said barrel having a muzzle portion adapted to receive a fastener device;

c. a handle secured to said housing and extending laterally therefrom; said handle including a slot for receiving a magazine containing a plurality of propellant charges;

d. follower means movably mounted in said handle slot and operative to push propellant charges through said slot and toward said housing;

e. first opposed wall means in said barrel forming a first portion of a split firing chamber;

f. second opposed wall means in said housing forming a second portion of said split firing chamber;

g. plunger means movably mounted in said handle and movable between a propellant pick-up position and a propellant loading position, said plunger means being operable to receive a propellant charge from said handle slot and wedge a propellant charge between one of said first and second opposed wall means independently of said follower means; and

h. means in said housing operative to ignite a propellant charge positioned in said split firing chamber.

12. A power actuated tool comprising:

a. a housing;

b. a barrel connected to said housing, said barrel having a muzzle portion adapted to receive a fastener device;

c. a handle secured to said housing and extending laterally therefrom, said handle including a slot for receiving a magazine containing a plurality of propellant charges, and at least a portion of said slot opening outwardly through a side wall of said handle;

(1. follower means movably mounted in said handle slot and operative to push propellant charges through said slot and toward said housing, said follower means further including a protuberance portion projecting through said slot opening for manual manipulation by an operator;

. a bolt assembly mounted in said housing, said bolt assembly having a nose portion of reduced diameter, and said nose portion having opposed wall means providing a side wall portion of a split firing chamber, said opposed wall means being operative to frictionally engage a propellant charge for positive positioning thereof;

f. plunger means movably mounted in said handle and operative to transfer a propellant charge from said handle slot to said opposed wall means; and

g. means in said bolt assembly operative to ignite a propellant charge positioned in said split firing chamber.

13. The tool of claim 12, wherein said handle slot includes a straight line portion and a terminal curvilinear portion extending from said straight line portion toward said plunger means, and said follower means includes a pivotally mounted propellant follower operative to move into said curvilinear portion to force a last remaining propellant charge from said slot to said plunger means.

14. The tool of claim 12, wherein said plunger means includes a springy member operative to grasp a propellant charge issuing from said slot, and further includes reciprocating means operative to force a propellant charge from said springy means and toward said opposed wall means.

15. The tool of claim 14, further comprising means operative to rotate said plunger means through substantially a ninety degree angle as said plunger means moves longitudinally from a propellant pickup position adjacent said slot, to

a propellant feeding position adjacent said opposed wall means.

16. The tool of claim 15, further comprising spring means operating to bias said plunger means toward said propellant pickup position.

17. The tool of claim 12, further comprising means in said slot operative to latch said follower means in a position remote from said housing to permit insertion and removal of a magazine to and from said slot.

18. The tool of claim 13, further comprising magazine means mounted in said straight line portion of said handle slot, said magazine means including a longitudinally extending gap in substantial registry with said slot opening to permit said propellant follower to pass through said magazine.

19. A power-actuated tool comprising:

a. a housing;

b. barrel means carried by said housing;

c. first wall means in said barrel means forming a first lateral portion of a firing chamber;

d. second wall means in said housing forming a second lateral portion of said firing chamber;

e. said first and second wall means being operative to be moved into circumferentially adjacent positions to provide side walls for said firing chamber and to further provide lateral contact with and support for a propellant charge positioned for firing in said firing chamber; and

f. means operative to ignite a propellant charge positioned in said firing chamber.

20. A power-actuated tool comprising:

a. a housing;

b. a barrel carried by said housing for reciprocal movement thereon;

c. first wall means in said barrel fon'ning a first lateral portion of a firing chamber;

d. at least a pair of forwardly protruding prongs mounted in said housing to provide second wall means forming a second lateral portion of said firing chamber, said prongs being positioned adjacent to said first wall means when said barrel is in a rearwardmost position whereby said first and second wall means are operative to provide lateral confinement of a propellant pellet positioned for firing in said firing chamber; and

e. means operative to ignite a propellant pellet positioned in said firing chamber.

21. A power-actuated tool comprising:

a. a housing;

b. a barrel carried by said housing, said barrel having a rearward portion including a cavity opening into said housing;

c. first means in said barrel cavity forming a first lateral portion of a split firing chamber;

d. bolt means mounted in said housing, said bolt means having a nose portion sized for telescoping disposition in said barrel cavity;

e. second means formed on said bolt nose and extending therefrom to form a second lateral portion of said split firing chamber, said second means being sized for adjacent positioning between said first means to combine therewith to provide a side wall of said split firing chamber;

f. one of said barrel and said bolt means being moveable with respect to the other thereof to displace said first means from said second means to open said split firing chamber for lateral insertion of a propellant pellet into frictional engagement with one of said first and second means; and

g. means operable to ignite a propellant pellet.

22. The tool of claim 21, further including means on said one of said first and second means operative to deform a propellant pellet to grip the latter.

23. A power-actuated tool comprising:

a. housing means;

b. barrel means carried by said housing means;

c. handle means secured to said housing means and extending laterally therefrom, said handle means including a slot, at least a portion of said slot opening outwardly through a side wall of said handle means;

d. hollow open ended magazine means mounted in said handle means slot, said magazine means including a longitudinally extending gap in registry with said slot opening; and

e. follower means movably mounted in said handle means slot for sliding movement into the interior of said magazine means, said follower means being operative to move through said magazine to push propellant charges through said magazine and toward said housing, said follower means including a protuberant portion projecting through said slot opening and said magazine gap for manual manipulation by an operator.

3,659,768 Dated May 2, 1972 Patent No.

Inventor-(s) Lawrence J, Brunelle It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Col. 6, line 37, please delete "Fl GS. DIGS.'.' and insert --to FIGS.

In Col. 9, line 16, please delete the first occurrence of "firing" and insert -=-first--;

Signed and sealed this 26th day of September 1972.

(SEAL) Attest:

EDWARD MQFLETCEHER,JRQ ROBERT GOTTSCHALK Attestlng Officer Commissioner of Patents -'ORM PO-10 0 (10-69) USCOMM-DC 60376-F59 Q U.S. GOVERNMENT PRINTING OFFICE: I969 O366334 

1. A power-actuated tool comprising: a. a housing; b. a barrel mounted in said housing; c. first opposed wall means in said barrel forming a first portion of a split firing chamber; d. second opposed wall means in said housing forming a second portion of said split firing chamber; e. said first and second wall means being operative to be moved into circumferentially adjacent positions to provide at least four-sided close confinement of a propellant charge positioned for firing in said split firing chamber, and further being operative to be moved into offset positions to permit a propellant charge to be inserted from a lateral direction into frictional engagement with one of said first and second means; and f. means in said housing operative to ignite a propellant charge positioned in said split firing chamber.
 2. A power-actuated tool comprising: a. a housing; b. a barrel mounted in said housing for reciprocal movement therein; c. a pair of opposed shoulders in said barrel providing first opposed wall means forming a first portion of a split firing chamber; d. a pair of opposed forwardly protruding prongs mounted in said housing to provide second opposed wall means forming a second portion of said split firing chamber, said prongs being telescoped between said opposed shoulders when said barrel is in a rearwardmost position whereby said first and second wall means circumferentially adjacent and operative to provide four-sided confinement of a propellant pellet positioned for firing in said split firing chamber; and e. means in said housing operative to ignite a propellant pellet positioned in said split firing chamber.
 3. A power-actuated tool comprising: a. a housing; b. a barrel mounted in said housing, said barrel having a rearward portion including a cavity opening into said housing; c. first opposed wall means in said barrel cavity forming top and bottom portions of a split firing chamber; d. bolt means mounted in said housing, said bolt means having a nose portion sized for telescoping containment in said barrel cavity; e. prong means formed on said bolt nose and extending therefrom to form lateral side portions of said split firing chamber, said prong means being sized for telescoping extension between said first wall means to combine therewith to provide a four-sided split firing chamber; f. one of said barrel and said bolt means being movable with respect to the other thereof to displace said first wall means from said prong means to open said split firing chamber for insertion of a caseless propellant pellet; and g. means in said housing operable to ignite a propellant pellet.
 4. The tool of claim 3, further including means on said prong means operative to deform a propellant pellet to grip the latter.
 5. A power actuated tool comprising: a. a housing; b. a barrel slidably connected to said housing and movable between a cocked position and a fired position; c. a firing pin slidably mounted in said housing and movable between a cocked position and fired position; d. firing spring means contacting said firing pin to bias the latter toward said fired position; e. slide means mounted in said housing and movable between a forward position and a rearward cocked position, said slide means including a portion aligned with said barrel to contact the latter when said barrel is moved rearwardly whereby said slide means is driven rearwardly to its cocKed position by said barrel; f. sear means pivotally mounted on said slide means and operable to engage said firing pin to cock the latter when said slide means is cocked; g. trigger means pivotally mounted on said housing, said trigger means including a plate projecting therefrom toward said slide means; and h. lug means projecting from said sear means for alignment with said trigger plate only when said slide means is in its cocked position, said trigger plate being operative to engage said sear lug, when said trigger is pulled, to pivot said rear means out of engagement with said firing pin to release the latter for movement toward its fired position.
 6. The tool of claim 5, further comprising spring means contacting said slide means to bias the latter toward its forward position.
 7. The tool of claim 5, further comprising second spring means contacting said firing pin to bias the latter a short predetermined distance away from its fired position after the tool is fired.
 8. A power-actuated tool comprising: a. housing means; b. barrel means slidably carried by said housing means, said barrel means including a relatively narrow slot extending longitudinally thereof; c. piston means mounted in said barrel means and movable between a fired position and a firing position; d. a firing chamber rearward of said piston means; e. pawl means mounted on said housing means and operative to engage said piston means to move the latter from its fired position to its firing position when said barrel means is moved forwardly with respect to said housing means, said pawl means extending through said barrel slot; and f. cylindrical means mounted on said housing for rotation about its own axis and operable independently of said pawl for engagement with an end wall of said slot in said barrel means to stop forward movement thereof at a plurality of selectable locations to position said piston means at any one of a number of different distances from said firing chamber to vary the power output of the tool with a given propellant load.
 9. The tool of claim 8, wherein said cylindrical means is a drum rotatably mounted on said housing, said drum having an end surface including steps longitudinally offset one from another, each of said steps being positionable in said barrel slot by rotation of said drum to align a step with said end wall of said barrel slot to stop forward movement of said barrel at a different location forward of said housing.
 10. The tool of claim 9, further comprising detent means operable to fix said drum against accidental rotational movement once a predetermined step is aligned with said barrel slot end wall.
 11. A power-actuated tool comprising: a. a housing; b. a barrel connected to said housing, said barrel having a muzzle portion adapted to receive a fastener device; c. a handle secured to said housing and extending laterally therefrom; said handle including a slot for receiving a magazine containing a plurality of propellant charges; d. follower means movably mounted in said handle slot and operative to push propellant charges through said slot and toward said housing; e. first opposed wall means in said barrel forming a first portion of a split firing chamber; f. second opposed wall means in said housing forming a second portion of said split firing chamber; g. plunger means movably mounted in said handle and movable between a propellant pick-up position and a propellant loading position, said plunger means being operable to receive a propellant charge from said handle slot and wedge a propellant charge between one of said first and second opposed wall means independently of said follower means; and h. means in said housing operative to ignite a propellant charge positioned in said split firing chamber.
 12. A power actuated tool comprising: a. a housing; b. a barrel connected to said housing, said barrel having a muzzle portion adapted to receive a fasteNer device; c. a handle secured to said housing and extending laterally therefrom, said handle including a slot for receiving a magazine containing a plurality of propellant charges, and at least a portion of said slot opening outwardly through a side wall of said handle; d. follower means movably mounted in said handle slot and operative to push propellant charges through said slot and toward said housing, said follower means further including a protuberance portion projecting through said slot opening for manual manipulation by an operator; e. a bolt assembly mounted in said housing, said bolt assembly having a nose portion of reduced diameter, and said nose portion having opposed wall means providing a side wall portion of a split firing chamber, said opposed wall means being operative to frictionally engage a propellant charge for positive positioning thereof; f. plunger means movably mounted in said handle and operative to transfer a propellant charge from said handle slot to said opposed wall means; and g. means in said bolt assembly operative to ignite a propellant charge positioned in said split firing chamber.
 13. The tool of claim 12, wherein said handle slot includes a straight line portion and a terminal curvilinear portion extending from said straight line portion toward said plunger means, and said follower means includes a pivotally mounted propellant follower operative to move into said curvilinear portion to force a last remaining propellant charge from said slot to said plunger means.
 14. The tool of claim 12, wherein said plunger means includes a springy member operative to grasp a propellant charge issuing from said slot, and further includes reciprocating means operative to force a propellant charge from said springy means and toward said opposed wall means.
 15. The tool of claim 14, further comprising means operative to rotate said plunger means through substantially a ninety degree angle as said plunger means moves longitudinally from a propellant pickup position adjacent said slot, to a propellant feeding position adjacent said opposed wall means.
 16. The tool of claim 15, further comprising spring means operating to bias said plunger means toward said propellant pickup position.
 17. The tool of claim 12, further comprising means in said slot operative to latch said follower means in a position remote from said housing to permit insertion and removal of a magazine to and from said slot.
 18. The tool of claim 13, further comprising magazine means mounted in said straight line portion of said handle slot, said magazine means including a longitudinally extending gap in substantial registry with said slot opening to permit said propellant follower to pass through said magazine.
 19. A power-actuated tool comprising: a. a housing; b. barrel means carried by said housing; c. first wall means in said barrel means forming a first lateral portion of a firing chamber; d. second wall means in said housing forming a second lateral portion of said firing chamber; e. said first and second wall means being operative to be moved into circumferentially adjacent positions to provide side walls for said firing chamber and to further provide lateral contact with and support for a propellant charge positioned for firing in said firing chamber; and f. means operative to ignite a propellant charge positioned in said firing chamber.
 20. A power-actuated tool comprising: a. a housing; b. a barrel carried by said housing for reciprocal movement thereon; c. first wall means in said barrel forming a first lateral portion of a firing chamber; d. at least a pair of forwardly protruding prongs mounted in said housing to provide second wall means forming a second lateral portion of said firing chamber, said prongs being positioned adjacent to said first wall means when said barrel is in a rearwardmost position whereby said first and second wall means are operative to proviDe lateral confinement of a propellant pellet positioned for firing in said firing chamber; and e. means operative to ignite a propellant pellet positioned in said firing chamber.
 21. A power-actuated tool comprising: a. a housing; b. a barrel carried by said housing, said barrel having a rearward portion including a cavity opening into said housing; c. first means in said barrel cavity forming a first lateral portion of a split firing chamber; d. bolt means mounted in said housing, said bolt means having a nose portion sized for telescoping disposition in said barrel cavity; e. second means formed on said bolt nose and extending therefrom to form a second lateral portion of said split firing chamber, said second means being sized for adjacent positioning between said first means to combine therewith to provide a side wall of said split firing chamber; f. one of said barrel and said bolt means being moveable with respect to the other thereof to displace said first means from said second means to open said split firing chamber for lateral insertion of a propellant pellet into frictional engagement with one of said first and second means; and g. means operable to ignite a propellant pellet.
 22. The tool of claim 21, further including means on said one of said first and second means operative to deform a propellant pellet to grip the latter.
 23. A power-actuated tool comprising: a. housing means; b. barrel means carried by said housing means; c. handle means secured to said housing means and extending laterally therefrom, said handle means including a slot, at least a portion of said slot opening outwardly through a side wall of said handle means; d. hollow open ended magazine means mounted in said handle means slot, said magazine means including a longitudinally extending gap in registry with said slot opening; and e. follower means movably mounted in said handle means slot for sliding movement into the interior of said magazine means, said follower means being operative to move through said magazine to push propellant charges through said magazine and toward said housing, said follower means including a protuberant portion projecting through said slot opening and said magazine gap for manual manipulation by an operator. 